Pulsed Laser Nanostructuring of Ceramic and Carbon Surfaces
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Solution Overview
Problem
Current methods for improving the wettability and adhesion of materials on ceramic, boron, silicon, and carbon surfaces are limited, as they often require chemical treatments and mechanical roughening, which can be complex and inefficient.
Innovation Solution
A method involving pulsed laser irradiation to create sub-micrometer surface structures, allowing for the production of nanostructured surfaces without the need for chemical pretreatment, which enhances adhesion of adhesives, paints, and biological tissues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If chemical treatments and mechanical roughening are used to improve adhesion, then wettability and adhesion of coatings are enhanced, but process complexity and treatment time increase
Solution Approach 1:
The patent replaces chemical treatments and mechanical roughening with laser irradiation, which uses optical energy to directly modify the surface. The laser beam (1064 nm wavelength) creates microstructured surfaces through photothermal effects, eliminating the need for chemical agents and mechanical equipment, thus reducing process complexity while maintaining adhesion improvement
Solution Approach 2:
The invention changes the surface properties by controlling laser parameters (wavelength 1064 nm, pulse duration, power density) to create specific microstructures. By adjusting these parameters, the surface achieves optimal wettability and adhesion without requiring multiple chemical treatment steps or mechanical processing stages
2Strength
If chemical treatments are applied to improve adhesion, then surface wettability increases, but additional adhesion promoters and chemicals are required
Solution Approach 1:
The patent substitutes chemical treatment methods with laser irradiation, which uses optical energy instead of chemical substances. The laser creates microstructured surfaces that inherently improve adhesion through increased surface area and mechanical interlocking, eliminating the need for adhesion promoters, silanes, or other chemical agents
Solution Approach 2:
The laser irradiation process itself creates the adhesion-improving surface structure directly on the substrate without requiring additional chemical substances. The surface modification is self-contained, with the laser energy directly transforming the surface morphology to achieve the desired adhesion properties
3Strength
If mechanical roughening is used to increase surface area, then adhesion improves, but surface structure control precision decreases
Solution Approach 1:
The patent replaces imprecise mechanical roughening with laser irradiation, which offers precise control over surface structure through optical focusing. The laser beam can be focused to specific spot sizes and scanned at controlled speeds, creating uniform microstructures with predictable dimensions and distribution, thereby achieving both adhesion improvement and manufacturing precision
Solution Approach 2:
The invention uses dynamic laser scanning parameters (scanning speed, pulse frequency, focus position) to control the resulting surface structure. By adjusting these dynamic parameters, the process adapts to create optimal microstructures for different substrates and application requirements, achieving precise control over surface area, roughness, and feature distribution
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method effectively increases the adhesion of various coatings and materials by creating nanostructures that cover a significant portion of the surface, improving the bonding process and reducing the need for additional adhesion promoters.
Implementation Method 1
A method is described for producing a surface which has surface structures with dimensions in the sub-micrometer range and is chemically modified compared to the initial surface by a single or multiple irradiation with a pulsed laser
Implementation Method 2
by laser ablation using simple optics or a simple configuration mask
Implementation Method 3
by a single or multiple irradiation with a pulsed laser under the conditions specified in the above-described procedure
Implementation Method 4
which ensure excellent adhesion of, for example, adhesives, paints, solder, sealants, bone cement, adhesion promoters or biological tissue
Data Source
Figure 1(a)~2
Figure 3~4
Figure 5(a)~5(b)
AI summary
Producing a surface that has surface structures with dimensions in the sub-micrometer range, comprises completely or repeatedly scanning a material of an outer surface, which does not yet have surface structures with dimensions in the sub-micrometer range and which is accessible to a laser beam irradiation, and in which the surface structures is to be formed, with a pulsed laser beam, such that adjacent light spots of the laser beam completely abut each other. The material of the surface is e.g. at least a ceramic and/or a metal alloy containing heat-conductive carbon-containing particles. Producing a surface that has surface structures with dimensions in the sub-micrometer range, comprises completely or repeatedly scanning a material of an outer surface, which does not yet have surface structures with dimensions in the sub-micrometer range and which is accessible to a laser beam irradiation, and in which the surface structures is to be formed, with a pulsed laser beam, such that adjacent light spots of the laser beam completely abut each other or overlap, satisfying the condition: epsilon is equal to ((P p) 2>x square root of P mx fx alpha x square root of tx square root of K/d 2>x square root of vx square root of T Lx square root of C px square root of lambda )x 10 3>, where: epsilon is 3000-0.07; P p is peak pulse power of the exiting laser radiation (kW); P m is average power of the exiting laser radiation (W); t is pulse length of the laser pulses, preferably 0.1-4000 ns; f is repetition rate of the laser pulses (kHz); v is scanning on the workpiece surface (mm/second); d is diameter of the laser beam on the workpiece; alpha = absorption of the laser radiation of the irradiated material at normal conditions; lambda is wavelength of the laser radiation, preferably 100-11000 nm; T L is melting temperature of the material at atmospheric pressure; C p is specific heat capacity (J/kgx K) under normal conditions; and K is thermal conductivity (W/mx K) under normal conditions. The material of the surface is at least a ceramic, at least one inorganic ceramic green-body, at least one inorganic glass, carbon, boron, silicon, at least one fiber and/or non-fibrous carbon and/or boron-containing composite material with carbon and/or ceramic matrix, at least one inorganic green-body of the above mentioned composite material, at least one metal-ceramic composite material, at least one composite material of a metal and/or a metal alloy containing heat-conductive carbon-containing and/or boron-containing particles and/or fibers optionally and at least partially coated with an oxide layer. The atmosphere in which the process takes place, is a reactive gas or gas mixture with respect to the surface under the process conditions, through which the material which is covered by the surface is chemically modified during or after the scanning with the pulsed laser beam with respect to its composition prior to scanning with the laser beam with the proviso that either before or after the scanning with the laser beam, an adhesion promoter is applied. An independent claim is also included for a workpiece comprising the surface, which comprises the material.